Discrete time-varying autoregressive moving average (ARMA) models are used to describe realistic earthquake ground motion time histories. Both amplitude and frequency nonstationarities are incorporated in the model. An iterative Kalman filtering scheme is introduced to identify the time-varying parameters of an ARMA model from an actual earthquake record. Several model verification tests are pe...

We investigate the sequence of great earthquakes over the past century. To examine whether the earthquake record includes temporal clustering, we identify aftershocks and remove those from the record. We focus on the recurrence time, defined as the time between two consecutive earthquakes. We study the variance in the recurrence time and the maximal recurrence time. Using these quantities, we c...

Wavelet analysis is a new mathematical technique and in the recent years enormous interest in application of engineering has been observed. This new technique is particularly suitable for non-stationary processes as in contrast to the Fourier transform (FT). The wavelet transform (WT) allows exceptional localization, both in time and frequency domains. The application of the WT to earthquake en...

Basic Quantities from Earthquake Records Earthquakes are complex, dynamic events. In order to describe and work with them, a vocabulary of terms is necessary. Terms describing the intensity or magnitude of an earthquake give the engineer a quick estimate of the degree of shaking and damage one would expect. Other values reflect the time history of the earthquake such as acceleration, velocity, ...

Approximate dynamic analysis of structures is achieved by fast wavelet transform (FWT). The loads are considered as time history earthquake loads. To reduce the computational work, FWT is used by which the number of points in the earthquake record are reduced. For this purpose, the theory of wavelets together with filter banks are used. The low and high pass filters are used for the decompositi...

iran is an active seismic region. earthquake damage is commonly controlled by three interacting factors including source and path characteristics, local geological and geotechnical conditions and type of the structures. obviously, all of this would require analysis and presentation of a large amount of geological, seismological and geotechnical data. in this paper, nonlinear geotechnical seismi...

In the present study using the wavelet theory (WT) and later the nonlinear spectrum response of the acceleration (NSRA) resulted in estimating a strong earthquake record for the structure to a degree of freedom. WT was used in order to estimate the acceleration of earthquake mapping with equal sampling method (WTESM). Therefore, at first, the acceleration recorded in an earthquake using WTESM w...

-The acceleration record of an earthquake ground motion is a nonstationary process with both amplitude and frequency content varying in time. The paper presents a general procedure for the analysis and simulation of strong earthquake ground motions based on parametric ARMA models to be used in computing structural response. Some computational results obtained in the analysis and simulation of g...